1. Field of the Invention
The present invention generally relates to a recording method and apparatus using a liquid printing device. More particularly, the present invention is directed to a transfer-type recording mechanism in which a liquid printing device prints a recording liquid on a layer of an intermediate transfer element provided on an intermediate transfer medium in response to an imaging signal to form an image on the layer of the intermediate transfer element, and then the image is transferred to a recording medium.
2. Description of the Related Art
A recording method using an ink jet recording device, in which a recording liquid containing a color agent, usually referred to as ink, is emitted as a droplet under control of an image signal representative of information to be printed as so to achieve recording of an image, is advantageous in that a structure of the ink jet recording device is comparatively simple and that a noise generated by its recording operation can be reduced to an almost negligible amount. However, printing quality problems associated with producing images directly on a recording medium using ink jet technology include variations in printing conditions and quality depending on a type of a recording medium, such as an overhead projector sheet, a synthetic paper, an ink jet-dedicated paper or other recording media. In addition, when printing on plain paper with a typical water-soluble ink, deterioration of printing resolution occurs because of ink liquid blur and ink liquid penetration problems (i.e., the ink liquid penetrates through the plain paper to a back surface of the plain paper) due to ink liquid migration through paper fibers. Further, there is another problem that a printed image which is not dried fully is degraded when the recorded medium is ejected from a recording apparatus.
A recording method designed to solve the above-mentioned problems is described in U.S. Pat. Nos. 4,528,156 and 5,099,256. This method is a so-called intermediate transfer method in which, first an ink image is produced on an intermediate transfer medium via an ink jet recorder, and then the ink image on the intermediate transfer medium is transferred from the transfer medium to a recording medium. Such an intermediate transfer method includes a significant feature that a recording head is arranged at a predetermined spacing between the recording head and the recording medium so as to prevent clogging of the recording head caused by contamination due to paper fragments and dust. However, when an ink liquid is printed on the transfer medium, the ink liquid spreads inadequately, flows and mixes when producing a multi-color image, thereby producing an inaccurate image. This phenomenon is herein referred to as xe2x80x9cink liquid crawlingxe2x80x9d.
In order to solve the above problems, Japanese Laid-Open Patent Application No. 62-92849 describes a transfer method in which, first an ink liquid is printed on an intermediate transfer medium, a large portion of a water content of the ink liquid formed thereon is evaporated to produce a condensed ink liquid, which is in turn transferred to a recording medium. This method has an advantageous affect that a vivid image can be obtained, but is not applicable to a high-speed recording, energy-saving and high-resolution recording system because frequently, thermal energies and devices are required for generating the condensed ink on the transfer medium.
Japanese Laid-Open Patent Application No. 3-55283 teaches another method based on the intermediate transfer method, in which an ejected ink provided on an ink transfer medium is cooled partially so as to solidify the ink and to achieve a recording. A local cooling of the ejected ink induces a formation of high viscosity of the ink which can be transferred to a recording medium.
Japanese Laid-Open Patent Application No. 5-200999 describes another method in which an ink liquid is printed on a transfer drum which includes a water-absorptive layer on its surface. A water content of the ink liquid is absorbed by the water-absorptive layer due to its high absorption ability so as to form a condensed ink thereon, and then it is transferred to a recording medium. An advantage of this method is that a vivid image formation can be accomplished, because only the condensed ink formed on the water-absorptive layer by absorbing water contained in the ink liquid can be transferred to the recording medium.
Like Japanese Laid-Open Patent Application No. 62-92849, the above two methods are not suitable for high-speed printing, the energy-saving and the high resolution printing system as well as a compact and a light apparatus, because of the same reasons described with respect to Japanese Laid-Open Patent Application No-62-92849.
Japanese Laid-Open Patent Application No. 7-89067 discloses another method based on an ink jet recording method, which permits a transfer efficiency and image formation to be improved. An ink droplet is discharged on an intermediate transfer layer having a surface carrying a surfactant for improving wettability to form an image thereon, which is in turn transferred to a recording medium. In general, a typical surface active agent has an inherent property that reduces surface tension of a solution. When a water-based ink droplet used in the ink jet recording method is discharged on such a layer, it is natural that reduction of surface tension between the ink droplet and the above layer occurs, thereby causing spreading of the ink droplet thereon. In other words, there is a disadvantage in that it is difficult to obtain a high resolution image with good sharpness because an overall dimension of the ink liquid is likely to spread on the layer coated by the surfactant in comparison with an ink liquid size ejected from a recording head. Moreover, since the ink liquid is transferred to a recording medium together with the surface active agent, an additional disadvantage is that ink liquid bleeding occurs due to co-penetration of the ink liquid and the surface active agent into the recording medium, such as a paper.
Japanese Laid-Open Patent Application No. 7-145576 describes a specialized ink with which a printing quality is independent of the type of a recording medium, and a transfer medium from which only an image part is separated. Because transfer based on this type is carried out at temperature of from about 200xc2x0 C. to about 300xc2x0 C. as a softening temperature of a separating layer, there is provided a problem of d high-speed recording and system reliability.
Japanese Laid-Open Patent Application No. 10-58664 discloses still another method in which an ink liquid containing a dye having a quaternary ammonium salt in the side chain is printed on an anionic ion- exchange resin layer on the uppermost layer of an intermediate transfer medium using an ink jet generator, and the ink liquid is modified through chemical action during transportation of the transfer medium and transferred to a recording medium. This method provides an advantage that a transfer efficiency can be improved. On the other hand; this method has a drawback in that, because of ion-exchangeable modification of a dye composition in the ink liquid with the ion-exchange resin layer, a color tone of the ink on the recording medium is changed subtly. Generally speaking, since the ion-exchange resin layer functions such that only an ion can be exchanged with another one and does not absorb water contained in ink liquids, the only dye composition of the ink liquid printed on the ion-exchange resin layer is subjected to chemical modification. Because a concentration of the ink liquid remains constant, the ink is transferred to the recording medium, thereby producing a problem that a transferred image experiences ink liquid blurring, penetration problems and color mixing. In addition, since an ammonia gas is generated upon heating the ion-exchange resin layer for reuse, there is provided a pollution problem. Additionally, this method does not meet the requirement for a high-speed printing, low energy consumption, high resolution printing, compact and light system with maintenance-free operation due to deterioration and reuse and the like for the ion-exchange resin layer.
Japanese Laid-Open Patent Application No. 11-188858 by the present applicant discloses a recording method and apparatus which use an intermediate transfer medium having a powder layer which is removably provided on the transfer medium to receive a liquid from a printing head. In this recording method, the liquid is emitted in response to an image signal to produce an image on the intermediate transfer medium, and then the image thereon is transferred to a recording medium. The powder layer is formed of a polymer powder with high water-absorbing ability, and is dissolvable and swellable by the liquid and causes an increase in viscosity of the liquid residing thereon prior to transfer to a final recording medium. However, this has a problem that there are required a dedicated cleaning members, such as a blade and a brush or the like for cleaning the unused powder remaining on the intermediate transfer medium after transfer to the recording medium.
In general, since an area of a background portion of the intermediate transfer medium is larger than that of an imaged part, a quantity of the powder for use in this type tends to become large. Additionally, when the powder in an unused state is allowed to stand for a long time, the powder on the intermediate transfer medium absorbs water to cause viscosity of the powder to be increased, thereby leading to occurrence of a problem that the powder having water absorbed can not be cleaned by the cleaning member.
Moreover, properties such as water resistance and light resistance for a dye-based ink liquid is usually inferior to that for a pigment-based ink liquid, although images formed by the former have high chroma and vivid color tones. Japanese Laid-Open Patent Application No. 54-68303 describes an ink liquid containing an aqueous organic ultraviolet stabilizer. However, this ink liquid causes a clogged recording head problem and another disadvantage in that ejection stability is unsatisfactory for the ink jet recording method in which the ink droplet is ejected.
The foregoing patents solve some problems associated with the ink jet recording which produces images on the recording medium, but the major problems of image feathering, color to color blur and liquid penetration have not been solved.
To overcome the problems described above, preferred embodiments of the present invention provide a recording method and apparatus based on a transfer-type recording mechanism, in which an unused powder after a transfer step is reused and a quantity of powder for use is limited to that used in an imaged area, and only deteriorated powder due to absorption of a moisture in air can be removed.
In one preferred embodiment of the present invention, a method of recording an image includes the steps of forming a layer of an intermediate transfer element removably on a surface of an intermediate transfer medium, the surface of the intermediate transfer medium having a substance which reacts with the intermediate transfer element, the layer being dissolvable and swellable by a liquid on the intermediate transfer medium and enabling a viscosity of the liquid residing thereon to be increased; producing an image on the intermediate transfer medium by supplying the liquid thereon from a recording head in response to an image signal; and transferring the image to a recording medium, wherein the intermediate transfer element remains on the intermediate transfer medium after transfer and is reused without removal.
According to another preferred embodiment of the present invention, an apparatus for recording an image includes a recording head for projecting a liquid; an intermediate transfer medium; a recording medium; and a layer of an intermediate transfer element formed removably on a surface of the intermediate transfer medium, the surface of the intermediate transfer medium formed of a substance which reacts with the intermediate transfer element, the layer being dissolvable and swellable by the liquid supplied on the intermediate transfer medium from the recording head in response to an image signal and enabling a viscosity of the liquid residing thereon to be increased so as to produce an image which is in turn transferred to the recording medium; and a cleaning member including a surface which has a poor releasing ability for the intermediate transfer element having an increased viscosity caused by the liquid or absorption of a moisture in air in comparison with the surface of the intermediate transfer medium, and the intermediate transfer element having the increased viscosity is removed from the intermediate transfer medium by contacting the cleaning member with the surface of the intermediate transfer medium after transfer to the recording medium.
Preferred embodiments of the present invention provides a recording method and apparatus in which only quantity of an intermediate transfer element consumed by a liquid can be supplied on an intermediate transfer medium so as to reuse the intermediate transfer element which is remaining on the medium, so that simplification of the apparatus and low cost operation due to reduction of the quantity of the intermediate transfer element can be realized.
Also, preferred embodiments of the present invention provide a recording method and apparatus based on a transfer-type recording mechanism having an intermediate transfer medium in order to improve a high-speed recording using a recording medium and light resistance of an image produced on the recording medium. A vivid image is instantaneously formed on the intermediate transfer medium so that the image is then transferred to a recording medium so as to produce an excellent transferred image with light and water resistance properties while eliminating liquid blur, color mixing and liquid penetration problems.
According to preferred embodiments of the present invention, there is provided a recording method and apparatus which prevent image blur due to liquid crawling and penetration problems of a transferred image on a recording medium using an intermediate transfer medium having a surface which has a water-absorptive layer for an ink liquid and exhibits an increased viscosity caused by water absorption, and improve light resistance of the transferred image by containing an ultraviolet stabilizer in the layer provided on the intermediate transfer medium, and eliminate recording head clogging because of inclusion of the ultraviolet stabilizer in the liquid.
According to a preferred embodiment of the present invention, there is provided a recording method in which an image on an intermediate transfer medium is produced by supplying a liquid thereon in response to an image signal, and the image is then transferred to a recording medium so as to record an image, the method including the steps of forming a layer of an intermediate transfer element removably on a surface of the intermediate transfer medium, the intermediate transfer element including a powder having a water-absorptive ability for the liquid and exhibiting an increased viscosity caused by water absorption and an ultraviolet stabilizer, the layer being dissolvable and swellable by the liquid on the surface of the intermediate transfer medium and enabling a viscosity of the liquid residing thereon to be increased; producing the image on the intermediate transfer medium by supplying the liquid on the surface of the intermediate transfer medium; and transferring the image on the intermediate transfer medium to the recording medium.
According to another preferred embodiment of the present invention, there is provided a recording apparatus in which an image on an intermediate transfer medium is produced by supplying a liquid thereon in response to an image signal, and then the image is then transferred to a recording medium so as to record an image, the apparatus including a forming portion for forming a layer of an intermediate transfer element on a surface of the intermediate transfer medium, the intermediate transfer element including a powder and an ultraviolet stabilizer, the layer being disposed removably on the intermediate transfer medium, the layer being dissolvable and swellable by the liquid on the intermediate transfer medium and enabling a viscosity of the liquid thereon to be increased; a liquid supplying portion for supplying the liquid on the intermediate transfer medium having a surface has the layer so as to produce the image thereon; and a transfer portion for transferring the image formed on the transfer medium to the recording medium.
According to preferred embodiments of the present invention, a high quality image having excellent sharpness and light resistance can be produced while suppressing ink liquid blur on a recording medium significantly.
It is still another preferred embodiment of the present invention, an improved recording method and apparatus is compact, light and energy-saving and based on transfer-type recording mechanism.
According to another preferred embodiment of the present invention, there is provided a recording method in which an image on an intermediate transfer medium is produced by supplying a liquid thereon from a recording head in response to an image signal and the image is then transferred to a recording medium, the recording method including the steps of forming a layer of an intermediate transfer element removably on a surface of the intermediate transfer medium, the intermediate transfer element formed of a powder mixture including a plurality of powders, each of which having different chemical and physical properties, the layer being dissolvable and swellable by the liquid on the intermediate transfer medium and enabling a viscosity of the liquid residing thereon to be increased; producing an image on the intermediate transfer medium by supplying the liquid thereon; and then transferring the image to the recording medium.
According to another preferred embodiment of the present invention, there is provided a recording apparatus including a recording head for projecting a liquid, an intermediate transfer medium and a recording medium, the liquid is supplied on the intermediate transfer medium from the recording head so as to produce an image thereon which is in turn transferred to the recording medium, the apparatus including a forming portion for forming a layer of an intermediate transfer element on a surface of the intermediate transfer medium, the intermediate transfer element including a powder mixture including a plurality of powders each having different chemical and physical properties, the layer formed removably on the intermediate transfer medium, the layer being dissolvable and swellable by the liquid on the intermediate transfer medium and enabling a viscosity of the liquid thereon to be increased, a liquid supplying portion for supplying the liquid on the intermediate transfer medium having a surface which includes a layer for producing an image thereon; a transfer portion for transferring the image formed with the powder mixture and the powder mixture forming the image produced on the intermediate transfer medium to the recording medium; and a cleaning portion for removing the powder mixture remaining on the intermediate transfer medium after transferring the image formed with the powder mixture and the powder mixture forming the image produced on the intermediate transfer medium to the recording medium.
According to another preferred embodiment of the present invention, it is possible to provide an improved recording method and apparatus which is compact, light and energy-saving. Furthermore, an improved transfer efficiency, a high-resolution image on the recording medium and the image formation on both surfaces can be achieved without image blur, color mixing and liquid penetration problems.